Newton's Third Law: Solving the Man & Sled Puzzle

AI Thread Summary
The man can move the sled despite the equal and opposite forces described by Newton's Third Law because he exerts more force through his feet against the ground than the sled does against the same surface. This difference in friction allows him to pull the sled forward. If the scenario were on ice, the sled would have less friction, requiring less force from the man to achieve movement. The interaction with the Earth plays a crucial role in this dynamic. Thus, the combination of friction and force application enables both the man and sled to move together.
brewAP2010
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Homework Statement


If a man pulls forward on a sled, and the sled pulls backward on the man with an equal amount of force, how can the man and sled move at all?


Homework Equations





The Attempt at a Solution

 
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Since the sled will move, you should think about what Newton's 2nd law says compared to his third law. What are your thoughts?
 
brewAP2010 said:
If a man pulls forward on a sled, and the sled pulls backward on the man with an equal amount of force, how can the man and sled move at all?

It is not only man and sled, but there is also the Earth they interact with.

ehild
 
He manages to move the sled by digging in his feet with more resistance than the sled can muster from its friction with the ground. If it were done on ice, he would not need to apply much force.
 

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